Block copolymers with different topologies (linear, loop, 3-armed and 4-armed polymers) containing poly(N-vinylpyrrrolidone) (PVP) antifouling blocks and terminal poly(dopamine-acrylamide) (PDAA) anchoring blocks were synthesized. These polymers can form a robust antifouling nanolayer on various surfaces. The morphologies of the polymer-modified surfaces are strongly dependent on the topologies of the polymers: with the increase of arm numbers, the morphology evolves from the smooth surface to the nanoscale coarse surface. As a result, the hydrophilicity of the coatings increases with the increase of degree of nanoscale roughness, and the 4-armed block copolymer forms a superhydrophilic surface with a water contact angle (WCA) as low as 8.7°. Accordingly, the linear diblock copolymer exhibits the worst antifouling efficiency, while the 4-armed polymer exhibits the best antifouling efficiency. This is the first example systematically showing that the antifouling efficacy could be adjusted simply by the topology of the coatings. Cell viability studies revealed that all of the copolymers exhibit excellent cytocompatibility. These biocompatible polymers with narrowly distributed molecular weight might find niches for antifouling applications in various areas such as anti-protein absorption, anti-bacterial and anti-marine fouling.